1. Field of the Invention
The present invention relates to a lens driving control apparatus for a zoom lens used in a TV broadcasting camera.
2. Description of Related Art
Operability and mobility are considered important for a color TV camera for TV broadcasting. To meet these requirements, image pickup devices for cameras of this kind have recently become smaller in size. A small CCD (solid-state image sensor) measuring, for example, only 2/3 or 1/2 inch has come to be most popularly used for reduction in size and weight of a camera as a whole. In view of this trend, zoom lenses for broadcasting color TV cameras also have come to be arranged smaller in size and lighter in weight and to have advanced specifications.
Thus, for specifications and attaining effects of images, it has become one of most important factors for a broadcasting TV camera, in particular, to shorten the so-called M.O.D. (minimum object distance), i.e., the nearest distance at which a zoom lens can take a picture of an object located in front of the zoom lens.
However, the efforts to shorten the M.O.D. encounter a problem that the angle of view (a photo-taking angle of view) is caused to vary by focusing. In a case where the zoom lens is arranged to make focus adjustment with a first lens group disposed foremost on the side of object among other lens groups, i.e., a front lens group, this problem particularly becomes manifest. An art for solving this problem has been known, for example, from a disclosure made in U.S. Pat. No. 4,083,057.